diff options
Diffstat (limited to 'src/com/android/camera/ui/focus/LensRangeCalculator.java')
-rw-r--r-- | src/com/android/camera/ui/focus/LensRangeCalculator.java | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/src/com/android/camera/ui/focus/LensRangeCalculator.java b/src/com/android/camera/ui/focus/LensRangeCalculator.java new file mode 100644 index 000000000..ef9cbaec7 --- /dev/null +++ b/src/com/android/camera/ui/focus/LensRangeCalculator.java @@ -0,0 +1,71 @@ +/* + * Copyright (C) 2015 The Android Open Source Project + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package com.android.camera.ui.focus; + +import android.annotation.TargetApi; +import android.hardware.camera2.CameraCharacteristics; +import android.os.Build.VERSION_CODES; + +import com.android.camera.ui.motion.LinearScale; + +/** + * Compute diopter range scale to convert lens focus distances into + * a ratio value. + */ +@TargetApi(VERSION_CODES.LOLLIPOP) +public class LensRangeCalculator { + + /** + * A NoOp linear scale for computing diopter values will always return 0 + */ + public static LinearScale getNoOp() { + return new LinearScale(0, 0, 0, 0); + } + + /** + * Compute the focus range from the camera characteristics and build + * a linear scale model that maps a focus distance to a ratio between + * the min and max range. + */ + public static LinearScale getDiopterToRatioCalculator(CameraCharacteristics characteristics) { + // From the android documentation: + // + // 0.0f represents farthest focus, and LENS_INFO_MINIMUM_FOCUS_DISTANCE + // represents the nearest focus the device can achieve. + // + // Example: + // + // Infinity Hyperfocal Minimum Camera + // <----------|-----------------------------| | + // [0.0] [0.31] [14.29] + Float nearest = characteristics.get(CameraCharacteristics.LENS_INFO_MINIMUM_FOCUS_DISTANCE); + Float hyperfocal = characteristics.get(CameraCharacteristics.LENS_INFO_HYPERFOCAL_DISTANCE); + + if (nearest == null && hyperfocal == null) { + return getNoOp(); + } + + nearest = (nearest == null) ? 0.0f : nearest; + hyperfocal = (hyperfocal == null) ? 0.0f : hyperfocal; + + if (nearest > hyperfocal) { + return new LinearScale(hyperfocal, nearest, 0, 1); + } + + return new LinearScale(nearest, hyperfocal, 0, 1); + } +} |